Presently, in the circulation and physical distribution industries, amounts of handling packages tend to increase, by the enlargement of the mail order market. For this reason, each of physical distribution industry companies works on automation of a physical distribution system.
Regarding conveyance and storage of packages in a warehouse, automation thereof is advancing using a belt conveyor or the like, but a transfer work to move a package to another place, such as discharging and picking, it is difficult to automate such a work, and thereby device for automatization is required.
As a device which has automated such a transfer work, a suction holding device which sucks a package by making a suction pad in contact with an upper surface of the package, and lifts and moves the package to a desired place is known.
In the case of using a general suction holding device, when an upper surface of a package is inclined to the horizontal surface due to collapse of the package, or when an upper surface itself of the package is curved, it is difficult to make a suction pad suck the upper surface of the package. In addition, in the case of taking out a package in a tall basket out using a general suction holding device, it is necessary to prepare a suction holding device which is long enough to reach the bottom surface of the tall basket, and accordingly the long suction holding device might come in contact with the ambient environment. For example, when an operation in which a plurality of suction pads are provided in parallel on a hand, and a plurality of packages are sucked and held simultaneously is thought of, if the sizes of the packages are different, the heights of the upper surfaces of the packages are different, and thereby it is difficult of suck the whole package simultaneously, to cause a transfer working time to become long.